This invention relates generally to integrated circuits and more particularly to controlling power consumption by an integrated circuit.
Integrated circuits (IC""s) are known to be used in a wide variety of electronic devices. For example, personal computers, cellular telephones, compact disk players, MP3 players, et cetera all include integrated circuits. Such integerated circuits are comprised of a plurality of functional circuit blocks that perform desired functions. Transistors, resistors and capacitors generally comprise the circuitry found in each circuit block.
As is known, transistor performance (e.g. transfer characteristics, on resistance, slew rate, et cetera) varies depending on the supply voltage. The lower the supply voltage, the lower the transistor performance and slew rate, but the less power it consumes. Conversely, the higher the supply voltage, the higher the performance and slew rate, but more power is consumed as such, the power consumption by an integrated circuit is very much dependent on the supply voltage and transistors that comprise the circuit blocks.
As processing speeds of microprocessors, digital signal processors, et cetera increase, such devices are capable of processing larger software applications in less time. While some applications push the processing engine to its processing speed limits, most applications do not. However, the processing engine must be designed to support the highest processing requirements. Thus, the processing engine needs to have a supply voltage and system clock to handle the most taxing applications. When the processing engine is executing less taxing applications, the voltage and system clock remain the same, thus power consumption of the integrated circuit remains the same even though the application could accurately be performed with a lower supply voltage and/or a lower system clock.
Therefore, a need exists for a method and apparatus that adjust the system clock and/or the supply voltage based on the processing capabilities of an integrated circuit and the application being performed to conserve power.